I notice Microsoft is releasing Windows Server 2008 Foundation for small businesses which doesn't include Hyper-V. How about a workstation version *with* Hyper-V?
There's a lot of interest among developers in using Windows Server 2008 (and of course, R2) as a high-end workstation. Including Hyper-V harnesses the power of quad-core machines so developers can simulate a complete, stable network with top-notch performance for Visual Studio 2008 debugging and compiling.
You just have to look at Convert your Windows Server 2008 to a Workstation! and posts like this to see that this concept is taking off. Microsoft would be better to accomodate developers, recognize the dissatisfaction with Vista, and profit from another market segment than push developers to skirt the intent of the server product's EULA.